js/src/jsatom.cpp

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is Mozilla Communicator client code, released
  17  * March 31, 1998.
  18  *
  19  * The Initial Developer of the Original Code is
  20  * Netscape Communications Corporation.
  21  * Portions created by the Initial Developer are Copyright (C) 1998
  22  * the Initial Developer. All Rights Reserved.
  23  *
  24  * Contributor(s):
  25  *
  26  * Alternatively, the contents of this file may be used under the terms of
  27  * either of the GNU General Public License Version 2 or later (the "GPL"),
  28  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  29  * in which case the provisions of the GPL or the LGPL are applicable instead
  30  * of those above. If you wish to allow use of your version of this file only
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  32  * use your version of this file under the terms of the MPL, indicate your
  33  * decision by deleting the provisions above and replace them with the notice
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  35  * the provisions above, a recipient may use your version of this file under
  36  * the terms of any one of the MPL, the GPL or the LGPL.
  37  *
  38  * ***** END LICENSE BLOCK ***** */
  39
  40 /*
  41  * JS atom table.
  42  */
  43 #include "jsstddef.h"
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include "jstypes.h"
  47 #include "jsutil.h" /* Added by JSIFY */
  48 #include "jshash.h" /* Added by JSIFY */
  49 #include "jsprf.h"
  50 #include "jsapi.h"
  51 #include "jsatom.h"
  52 #include "jscntxt.h"
  53 #include "jsversion.h"
  54 #include "jsgc.h"
  55 #include "jslock.h"
  56 #include "jsnum.h"
  57 #include "jsscan.h"
  58 #include "jsstr.h"
  59
  60 const char *
  61 js_AtomToPrintableString(JSContext *cx, JSAtom *atom)
  62 {
  63     return js_ValueToPrintableString(cx, ATOM_KEY(atom));
  64 }
  65
  66 #define JS_PROTO(name,code,init) const char js_##name##_str[] = #name;
  67 #include "jsproto.tbl"
  68 #undef JS_PROTO
  69
  70 /*
  71  * String constants for common atoms defined in JSAtomState starting from
  72  * JSAtomState.emptyAtom until JSAtomState.lazy.
  73  *
  74  * The elements of the array after the first empty string define strings
  75  * corresponding to the two boolean literals, false and true, followed by the
  76  * JSType enumerators from jspubtd.h starting with "undefined" for JSTYPE_VOID
  77  * (which is pseudo-boolean 2) and continuing as initialized below. The static
  78  * asserts check these relations.
  79  */
  80 JS_STATIC_ASSERT(JSTYPE_LIMIT == 8);
  81 JS_STATIC_ASSERT(JSVAL_TO_BOOLEAN(JSVAL_VOID) == 2);
  82 JS_STATIC_ASSERT(JSTYPE_VOID == 0);
  83
  84 const char *const js_common_atom_names[] = {
  85     "",                         /* emptyAtom                    */
  86     js_false_str,               /* booleanAtoms[0]              */
  87     js_true_str,                /* booleanAtoms[1]              */
  88     js_undefined_str,           /* typeAtoms[JSTYPE_VOID]       */
  89     js_object_str,              /* typeAtoms[JSTYPE_OBJECT]     */
  90     js_function_str,            /* typeAtoms[JSTYPE_FUNCTION]   */
  91     "string",                   /* typeAtoms[JSTYPE_STRING]     */
  92     "number",                   /* typeAtoms[JSTYPE_NUMBER]     */
  93     "boolean",                  /* typeAtoms[JSTYPE_BOOLEAN]    */
  94     js_null_str,                /* typeAtoms[JSTYPE_NULL]       */
  95     "xml",                      /* typeAtoms[JSTYPE_XML]        */
  96     js_null_str,                /* nullAtom                     */
  97
  98 #define JS_PROTO(name,code,init) js_##name##_str,
  99 #include "jsproto.tbl"
 100 #undef JS_PROTO
 101
 102     js_anonymous_str,           /* anonymousAtom                */
 103     js_apply_str,               /* applyAtom                    */
 104     js_arguments_str,           /* argumentsAtom                */
 105     js_arity_str,               /* arityAtom                    */
 106     js_call_str,                /* callAtom                     */
 107     js_callee_str,              /* calleeAtom                   */
 108     js_caller_str,              /* callerAtom                   */
 109     js_class_prototype_str,     /* classPrototypeAtom           */
 110     js_constructor_str,         /* constructorAtom              */
 111     js_count_str,               /* countAtom                    */
 112     js_each_str,                /* eachAtom                     */
 113     js_eval_str,                /* evalAtom                     */
 114     js_fileName_str,            /* fileNameAtom                 */
 115     js_get_str,                 /* getAtom                      */
 116     js_getter_str,              /* getterAtom                   */
 117     js_index_str,               /* indexAtom                    */
 118     js_input_str,               /* inputAtom                    */
 119     js_iterator_str,            /* iteratorAtom                 */
 120     js_length_str,              /* lengthAtom                   */
 121     js_lineNumber_str,          /* lineNumberAtom               */
 122     js_message_str,             /* messageAtom                  */
 123     js_name_str,                /* nameAtom                     */
 124     js_next_str,                /* nextAtom                     */
 125     js_noSuchMethod_str,        /* noSuchMethodAtom             */
 126     js_parent_str,              /* parentAtom                   */
 127     js_proto_str,               /* protoAtom                    */
 128     js_set_str,                 /* setAtom                      */
 129     js_setter_str,              /* setterAtom                   */
 130     js_stack_str,               /* stackAtom                    */
 131     js_toLocaleString_str,      /* toLocaleStringAtom           */
 132     js_toSource_str,            /* toSourceAtom                 */
 133     js_toString_str,            /* toStringAtom                 */
 134     js_valueOf_str,             /* valueOfAtom                  */
 135     js_toJSON_str,              /* toJSONAtom                   */
 136     "(void 0)",                 /* void0Atom                    */
 137
 138 #if JS_HAS_XML_SUPPORT
 139     js_etago_str,               /* etagoAtom                    */
 140     js_namespace_str,           /* namespaceAtom                */
 141     js_ptagc_str,               /* ptagcAtom                    */
 142     js_qualifier_str,           /* qualifierAtom                */
 143     js_space_str,               /* spaceAtom                    */
 144     js_stago_str,               /* stagoAtom                    */
 145     js_star_str,                /* starAtom                     */
 146     js_starQualifier_str,       /* starQualifierAtom            */
 147     js_tagc_str,                /* tagcAtom                     */
 148     js_xml_str,                 /* xmlAtom                      */
 149 #endif
 150
 151 #ifdef NARCISSUS
 152     js___call___str,            /* __call__Atom                 */
 153     js___construct___str,       /* __construct__Atom            */
 154     js___hasInstance___str,     /* __hasInstance__Atom          */
 155     js_ExecutionContext_str,    /* ExecutionContextAtom         */
 156     js_current_str,             /* currentAtom                  */
 157 #endif
 158 };
 159
 160 JS_STATIC_ASSERT(JS_ARRAY_LENGTH(js_common_atom_names) * sizeof(JSAtom *) ==
 161                  LAZY_ATOM_OFFSET_START - ATOM_OFFSET_START);
 162
 163 /*
 164  * Interpreter macros called by the trace recorder assume common atom indexes
 165  * fit in one byte of immediate operand.
 166  */
 167 JS_STATIC_ASSERT(JS_ARRAY_LENGTH(js_common_atom_names) < 256);
 168
 169 const size_t js_common_atom_count = JS_ARRAY_LENGTH(js_common_atom_names);
 170
 171 const char js_anonymous_str[]       = "anonymous";
 172 const char js_apply_str[]           = "apply";
 173 const char js_arguments_str[]       = "arguments";
 174 const char js_arity_str[]           = "arity";
 175 const char js_call_str[]            = "call";
 176 const char js_callee_str[]          = "callee";
 177 const char js_caller_str[]          = "caller";
 178 const char js_class_prototype_str[] = "prototype";
 179 const char js_constructor_str[]     = "constructor";
 180 const char js_count_str[]           = "__count__";
 181 const char js_each_str[]            = "each";
 182 const char js_eval_str[]            = "eval";
 183 const char js_fileName_str[]        = "fileName";
 184 const char js_get_str[]             = "get";
 185 const char js_getter_str[]          = "getter";
 186 const char js_index_str[]           = "index";
 187 const char js_input_str[]           = "input";
 188 const char js_iterator_str[]        = "__iterator__";
 189 const char js_length_str[]          = "length";
 190 const char js_lineNumber_str[]      = "lineNumber";
 191 const char js_message_str[]         = "message";
 192 const char js_name_str[]            = "name";
 193 const char js_next_str[]            = "next";
 194 const char js_noSuchMethod_str[]    = "__noSuchMethod__";
 195 const char js_object_str[]          = "object";
 196 const char js_parent_str[]          = "__parent__";
 197 const char js_proto_str[]           = "__proto__";
 198 const char js_setter_str[]          = "setter";
 199 const char js_set_str[]             = "set";
 200 const char js_stack_str[]           = "stack";
 201 const char js_toSource_str[]        = "toSource";
 202 const char js_toString_str[]        = "toString";
 203 const char js_toLocaleString_str[]  = "toLocaleString";
 204 const char js_undefined_str[]       = "undefined";
 205 const char js_valueOf_str[]         = "valueOf";
 206 const char js_toJSON_str[]          = "toJSON";
 207
 208 #if JS_HAS_XML_SUPPORT
 209 const char js_etago_str[]           = "</";
 210 const char js_namespace_str[]       = "namespace";
 211 const char js_ptagc_str[]           = "/>";
 212 const char js_qualifier_str[]       = "::";
 213 const char js_space_str[]           = " ";
 214 const char js_stago_str[]           = "<";
 215 const char js_star_str[]            = "*";
 216 const char js_starQualifier_str[]   = "*::";
 217 const char js_tagc_str[]            = ">";
 218 const char js_xml_str[]             = "xml";
 219 #endif
 220
 221 #if JS_HAS_GENERATORS
 222 const char js_close_str[]           = "close";
 223 const char js_send_str[]            = "send";
 224 #endif
 225
 226 #ifdef NARCISSUS
 227 const char js___call___str[]         = "__call__";
 228 const char js___construct___str[]    = "__construct__";
 229 const char js___hasInstance___str[]  = "__hasInstance__";
 230 const char js_ExecutionContext_str[] = "ExecutionContext";
 231 const char js_current_str[]          = "current";
 232 #endif
 233
 234 /*
 235  * JSAtomState.doubleAtoms and JSAtomState.stringAtoms hashtable entry. To
 236  * support pinned and interned string atoms, we use the lowest bits of the
 237  * keyAndFlags field to store ATOM_PINNED and ATOM_INTERNED flags.
 238  */
 239 typedef struct JSAtomHashEntry {
 240     JSDHashEntryHdr hdr;
 241     jsuword         keyAndFlags;
 242 } JSAtomHashEntry;
 243
 244 #define ATOM_ENTRY_FLAG_MASK            (ATOM_PINNED | ATOM_INTERNED)
 245
 246 JS_STATIC_ASSERT(ATOM_ENTRY_FLAG_MASK < JSVAL_ALIGN);
 247
 248 /*
 249  * Helper macros to access and modify JSAtomHashEntry.
 250  */
 251 #define TO_ATOM_ENTRY(hdr)              ((JSAtomHashEntry *) hdr)
 252 #define ATOM_ENTRY_KEY(entry)                                                 \
 253     ((void *)((entry)->keyAndFlags & ~ATOM_ENTRY_FLAG_MASK))
 254 #define ATOM_ENTRY_FLAGS(entry)                                               \
 255     ((uintN)((entry)->keyAndFlags & ATOM_ENTRY_FLAG_MASK))
 256 #define INIT_ATOM_ENTRY(entry, key)                                           \
 257     ((void)((entry)->keyAndFlags = (jsuword)(key)))
 258 #define ADD_ATOM_ENTRY_FLAGS(entry, flags)                                    \
 259     ((void)((entry)->keyAndFlags |= (jsuword)(flags)))
 260 #define CLEAR_ATOM_ENTRY_FLAGS(entry, flags)                                  \
 261     ((void)((entry)->keyAndFlags &= ~(jsuword)(flags)))
 262
 263 static JSDHashNumber
 264 HashDouble(JSDHashTable *table, const void *key);
 265
 266 static JSBool
 267 MatchDouble(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key);
 268
 269 static JSDHashNumber
 270 HashString(JSDHashTable *table, const void *key);
 271
 272 static JSBool
 273 MatchString(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key);
 274
 275 static const JSDHashTableOps DoubleHashOps = {
 276     JS_DHashAllocTable,
 277     JS_DHashFreeTable,
 278     HashDouble,
 279     MatchDouble,
 280     JS_DHashMoveEntryStub,
 281     JS_DHashClearEntryStub,
 282     JS_DHashFinalizeStub,
 283     NULL
 284 };
 285
 286 static const JSDHashTableOps StringHashOps = {
 287     JS_DHashAllocTable,
 288     JS_DHashFreeTable,
 289     HashString,
 290     MatchString,
 291     JS_DHashMoveEntryStub,
 292     JS_DHashClearEntryStub,
 293     JS_DHashFinalizeStub,
 294     NULL
 295 };
 296
 297 #define IS_DOUBLE_TABLE(table)      ((table)->ops == &DoubleHashOps)
 298 #define IS_STRING_TABLE(table)      ((table)->ops == &StringHashOps)
 299
 300 #define IS_INITIALIZED_STATE(state) IS_DOUBLE_TABLE(&(state)->doubleAtoms)
 301
 302 static JSDHashNumber
 303 HashDouble(JSDHashTable *table, const void *key)
 304 {
 305     jsdouble d;
 306
 307     JS_ASSERT(IS_DOUBLE_TABLE(table));
 308     d = *(jsdouble *)key;
 309     return JSDOUBLE_HI32(d) ^ JSDOUBLE_LO32(d);
 310 }
 311
 312 static JSDHashNumber
 313 HashString(JSDHashTable *table, const void *key)
 314 {
 315     JS_ASSERT(IS_STRING_TABLE(table));
 316     return js_HashString((JSString *)key);
 317 }
 318
 319 static JSBool
 320 MatchDouble(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key)
 321 {
 322     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 323     jsdouble d1, d2;
 324
 325     JS_ASSERT(IS_DOUBLE_TABLE(table));
 326     if (entry->keyAndFlags == 0) {
 327         /* See comments in MatchString. */
 328         return JS_FALSE;
 329     }
 330
 331     d1 = *(jsdouble *)ATOM_ENTRY_KEY(entry);
 332     d2 = *(jsdouble *)key;
 333     if (JSDOUBLE_IS_NaN(d1))
 334         return JSDOUBLE_IS_NaN(d2);
 335 #if defined(XP_WIN)
 336     /* XXX MSVC miscompiles such that (NaN == 0) */
 337     if (JSDOUBLE_IS_NaN(d2))
 338         return JS_FALSE;
 339 #endif
 340     return d1 == d2;
 341 }
 342
 343 static JSBool
 344 MatchString(JSDHashTable *table, const JSDHashEntryHdr *hdr, const void *key)
 345 {
 346     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 347
 348     JS_ASSERT(IS_STRING_TABLE(table));
 349     if (entry->keyAndFlags == 0) {
 350         /*
 351          * This happens when js_AtomizeString adds a new hash entry and
 352          * releases the lock but before it takes the lock the second time to
 353          * initialize keyAndFlags for the entry.
 354          *
 355          * We always return false for such entries so JS_DHashTableOperate
 356          * never finds them. We clean them during GC's sweep phase.
 357          *
 358          * It means that with a contested lock or when GC is triggered outside
 359          * the lock we may end up adding two entries, but this is a price for
 360          * simpler code.
 361          */
 362         return JS_FALSE;
 363     }
 364     return js_EqualStrings((JSString *)ATOM_ENTRY_KEY(entry), (JSString *)key);
 365 }
 366
 367 /*
 368  * For a browser build from 2007-08-09 after the browser starts up there are
 369  * just 55 double atoms, but over 15000 string atoms. Not to penalize more
 370  * economical embeddings allocating too much memory initially we initialize
 371  * atomized strings with just 1K entries.
 372  */
 373 #define JS_STRING_HASH_COUNT   1024
 374 #define JS_DOUBLE_HASH_COUNT   64
 375
 376 JSBool
 377 js_InitAtomState(JSRuntime *rt)
 378 {
 379     JSAtomState *state = &rt->atomState;
 380
 381    /*
 382     * The caller must zero the state before calling this function.
 383     */
 384     JS_ASSERT(!state->stringAtoms.ops);
 385     JS_ASSERT(!state->doubleAtoms.ops);
 386
 387     if (!JS_DHashTableInit(&state->stringAtoms, &StringHashOps,
 388                            NULL, sizeof(JSAtomHashEntry),
 389                            JS_DHASH_DEFAULT_CAPACITY(JS_STRING_HASH_COUNT))) {
 390         state->stringAtoms.ops = NULL;
 391         return JS_FALSE;
 392     }
 393     JS_ASSERT(IS_STRING_TABLE(&state->stringAtoms));
 394
 395     if (!JS_DHashTableInit(&state->doubleAtoms, &DoubleHashOps,
 396                            NULL, sizeof(JSAtomHashEntry),
 397                            JS_DHASH_DEFAULT_CAPACITY(JS_DOUBLE_HASH_COUNT))) {
 398         state->doubleAtoms.ops = NULL;
 399         JS_DHashTableFinish(&state->stringAtoms);
 400         state->stringAtoms.ops = NULL;
 401         return JS_FALSE;
 402     }
 403     JS_ASSERT(IS_DOUBLE_TABLE(&state->doubleAtoms));
 404
 405 #ifdef JS_THREADSAFE
 406     js_InitLock(&state->lock);
 407 #endif
 408     JS_ASSERT(IS_INITIALIZED_STATE(state));
 409     return JS_TRUE;
 410 }
 411
 412 static JSDHashOperator
 413 js_string_uninterner(JSDHashTable *table, JSDHashEntryHdr *hdr,
 414                      uint32 number, void *arg)
 415 {
 416     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 417     JSRuntime *rt = (JSRuntime *)arg;
 418     JSString *str;
 419
 420     /*
 421      * Any string entry that remains at this point must be initialized, as the
 422      * last GC should clean any uninitialized ones.
 423      */
 424     JS_ASSERT(IS_STRING_TABLE(table));
 425     JS_ASSERT(entry->keyAndFlags != 0);
 426     str = (JSString *)ATOM_ENTRY_KEY(entry);
 427
 428     /* Pass null as context. */
 429     js_FinalizeStringRT(rt, str, js_GetExternalStringGCType(str), NULL);
 430     return JS_DHASH_NEXT;
 431 }
 432
 433 void
 434 js_FinishAtomState(JSRuntime *rt)
 435 {
 436     JSAtomState *state = &rt->atomState;
 437
 438     if (!IS_INITIALIZED_STATE(state)) {
 439         /*
 440          * We are called with uninitialized state when JS_NewRuntime fails and
 441          * calls JS_DestroyRuntime on a partially initialized runtime.
 442          */
 443         return;
 444     }
 445
 446     JS_DHashTableEnumerate(&state->stringAtoms, js_string_uninterner, rt);
 447     JS_DHashTableFinish(&state->stringAtoms);
 448     JS_DHashTableFinish(&state->doubleAtoms);
 449
 450 #ifdef JS_THREADSAFE
 451     js_FinishLock(&state->lock);
 452 #endif
 453 #ifdef DEBUG
 454     memset(state, JS_FREE_PATTERN, sizeof *state);
 455 #endif
 456 }
 457
 458 JSBool
 459 js_InitCommonAtoms(JSContext *cx)
 460 {
 461     JSAtomState *state = &cx->runtime->atomState;
 462     uintN i;
 463     JSAtom **atoms;
 464
 465     atoms = COMMON_ATOMS_START(state);
 466     for (i = 0; i < JS_ARRAY_LENGTH(js_common_atom_names); i++, atoms++) {
 467         *atoms = js_Atomize(cx, js_common_atom_names[i],
 468                             strlen(js_common_atom_names[i]), ATOM_PINNED);
 469         if (!*atoms)
 470             return JS_FALSE;
 471     }
 472     JS_ASSERT((uint8 *)atoms - (uint8 *)state == LAZY_ATOM_OFFSET_START);
 473     memset(atoms, 0, ATOM_OFFSET_LIMIT - LAZY_ATOM_OFFSET_START);
 474
 475     return JS_TRUE;
 476 }
 477
 478 static JSDHashOperator
 479 js_atom_unpinner(JSDHashTable *table, JSDHashEntryHdr *hdr,
 480                  uint32 number, void *arg)
 481 {
 482     JS_ASSERT(IS_STRING_TABLE(table));
 483     CLEAR_ATOM_ENTRY_FLAGS(TO_ATOM_ENTRY(hdr), ATOM_PINNED);
 484     return JS_DHASH_NEXT;
 485 }
 486
 487 void
 488 js_FinishCommonAtoms(JSContext *cx)
 489 {
 490     JSAtomState *state = &cx->runtime->atomState;
 491
 492     JS_DHashTableEnumerate(&state->stringAtoms, js_atom_unpinner, NULL);
 493 #ifdef DEBUG
 494     memset(COMMON_ATOMS_START(state), JS_FREE_PATTERN,
 495            ATOM_OFFSET_LIMIT - ATOM_OFFSET_START);
 496 #endif
 497 }
 498
 499 static JSDHashOperator
 500 js_locked_atom_tracer(JSDHashTable *table, JSDHashEntryHdr *hdr,
 501                       uint32 number, void *arg)
 502 {
 503     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 504     JSTracer *trc = (JSTracer *)arg;
 505
 506     if (entry->keyAndFlags == 0) {
 507         /* Ignore uninitialized entries during tracing. */
 508         return JS_DHASH_NEXT;
 509     }
 510     JS_SET_TRACING_INDEX(trc, "locked_atom", (size_t)number);
 511     JS_CallTracer(trc, ATOM_ENTRY_KEY(entry),
 512                   IS_STRING_TABLE(table) ? JSTRACE_STRING : JSTRACE_DOUBLE);
 513     return JS_DHASH_NEXT;
 514 }
 515
 516 static JSDHashOperator
 517 js_pinned_atom_tracer(JSDHashTable *table, JSDHashEntryHdr *hdr,
 518                         uint32 number, void *arg)
 519 {
 520     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 521     JSTracer *trc = (JSTracer *)arg;
 522     uintN flags = ATOM_ENTRY_FLAGS(entry);
 523
 524     JS_ASSERT(IS_STRING_TABLE(table));
 525     if (flags & (ATOM_PINNED | ATOM_INTERNED)) {
 526         JS_SET_TRACING_INDEX(trc,
 527                              flags & ATOM_PINNED
 528                              ? "pinned_atom"
 529                              : "interned_atom",
 530                              (size_t)number);
 531         JS_CallTracer(trc, ATOM_ENTRY_KEY(entry), JSTRACE_STRING);
 532     }
 533     return JS_DHASH_NEXT;
 534 }
 535
 536 void
 537 js_TraceAtomState(JSTracer *trc, JSBool allAtoms)
 538 {
 539     JSAtomState *state;
 540
 541     state = &trc->context->runtime->atomState;
 542     if (allAtoms) {
 543         JS_DHashTableEnumerate(&state->doubleAtoms, js_locked_atom_tracer, trc);
 544         JS_DHashTableEnumerate(&state->stringAtoms, js_locked_atom_tracer, trc);
 545     } else {
 546         JS_DHashTableEnumerate(&state->stringAtoms, js_pinned_atom_tracer, trc);
 547     }
 548 }
 549
 550 static JSDHashOperator
 551 js_atom_sweeper(JSDHashTable *table, JSDHashEntryHdr *hdr,
 552                 uint32 number, void *arg)
 553 {
 554     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 555     JSContext *cx = (JSContext *)arg;
 556
 557     /* Remove uninitialized entries.  */
 558     if (entry->keyAndFlags == 0)
 559         return JS_DHASH_REMOVE;
 560
 561     if (ATOM_ENTRY_FLAGS(entry) & (ATOM_PINNED | ATOM_INTERNED)) {
 562         /* Pinned or interned key cannot be finalized. */
 563         JS_ASSERT(!js_IsAboutToBeFinalized(cx, ATOM_ENTRY_KEY(entry)));
 564     } else if (js_IsAboutToBeFinalized(cx, ATOM_ENTRY_KEY(entry))) {
 565         /* Remove entries with things about to be GC'ed. */
 566         return JS_DHASH_REMOVE;
 567     }
 568     return JS_DHASH_NEXT;
 569 }
 570
 571 void
 572 js_SweepAtomState(JSContext *cx)
 573 {
 574     JSAtomState *state = &cx->runtime->atomState;
 575
 576     JS_DHashTableEnumerate(&state->doubleAtoms, js_atom_sweeper, cx);
 577     JS_DHashTableEnumerate(&state->stringAtoms, js_atom_sweeper, cx);
 578
 579     /*
 580      * Optimize for simplicity and mutate table generation numbers even if the
 581      * sweeper has not removed any entries.
 582      */
 583     state->doubleAtoms.generation++;
 584     state->stringAtoms.generation++;
 585 }
 586
 587 JSAtom *
 588 js_AtomizeDouble(JSContext *cx, jsdouble d)
 589 {
 590     JSAtomState *state;
 591     JSDHashTable *table;
 592     JSAtomHashEntry *entry;
 593     uint32 gen;
 594     jsdouble *key;
 595     jsval v;
 596
 597     state = &cx->runtime->atomState;
 598     table = &state->doubleAtoms;
 599
 600     JS_LOCK(cx, &state->lock);
 601     entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, &d, JS_DHASH_ADD));
 602     if (!entry)
 603         goto failed_hash_add;
 604     if (entry->keyAndFlags == 0) {
 605         gen = ++table->generation;
 606         JS_UNLOCK(cx, &state->lock);
 607
 608         key = js_NewWeaklyRootedDouble(cx, d);
 609         if (!key)
 610             return NULL;
 611
 612         JS_LOCK(cx, &state->lock);
 613         if (table->generation == gen) {
 614             JS_ASSERT(entry->keyAndFlags == 0);
 615         } else {
 616             entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, key,
 617                                                        JS_DHASH_ADD));
 618             if (!entry)
 619                 goto failed_hash_add;
 620             if (entry->keyAndFlags != 0)
 621                 goto finish;
 622             ++table->generation;
 623         }
 624         INIT_ATOM_ENTRY(entry, key);
 625     }
 626
 627   finish:
 628     v = DOUBLE_TO_JSVAL((jsdouble *)ATOM_ENTRY_KEY(entry));
 629     cx->weakRoots.lastAtom = v;
 630     JS_UNLOCK(cx, &state->lock);
 631
 632     return (JSAtom *)v;
 633
 634   failed_hash_add:
 635     JS_UNLOCK(cx, &state->lock);
 636     JS_ReportOutOfMemory(cx);
 637     return NULL;
 638 }
 639
 640 JSAtom *
 641 js_AtomizeString(JSContext *cx, JSString *str, uintN flags)
 642 {
 643     jsval v;
 644     JSAtomState *state;
 645     JSDHashTable *table;
 646     JSAtomHashEntry *entry;
 647     JSString *key;
 648     uint32 gen;
 649
 650     JS_ASSERT(!(flags & ~(ATOM_PINNED|ATOM_INTERNED|ATOM_TMPSTR|ATOM_NOCOPY)));
 651     JS_ASSERT_IF(flags & ATOM_NOCOPY, flags & ATOM_TMPSTR);
 652
 653     state = &cx->runtime->atomState;
 654     table = &state->stringAtoms;
 655
 656     JS_LOCK(cx, &state->lock);
 657     entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, str, JS_DHASH_ADD));
 658     if (!entry)
 659         goto failed_hash_add;
 660     if (entry->keyAndFlags != 0) {
 661         key = (JSString *)ATOM_ENTRY_KEY(entry);
 662     } else {
 663         /*
 664          * We created a new hashtable entry. Unless str is already allocated
 665          * from the GC heap and flat, we have to release state->lock as
 666          * string construction is a complex operation. For example, it can
 667          * trigger GC which may rehash the table and make the entry invalid.
 668          */
 669         ++table->generation;
 670         if (!(flags & ATOM_TMPSTR) && JSSTRING_IS_FLAT(str)) {
 671             JSFLATSTR_CLEAR_MUTABLE(str);
 672             key = str;
 673         } else {
 674             gen = table->generation;
 675             JS_UNLOCK(cx, &state->lock);
 676
 677             if (flags & ATOM_TMPSTR) {
 678                 if (flags & ATOM_NOCOPY) {
 679                     key = js_NewString(cx, JSFLATSTR_CHARS(str),
 680                                        JSFLATSTR_LENGTH(str));
 681                     if (!key)
 682                         return NULL;
 683
 684                     /* Finish handing off chars to the GC'ed key string. */
 685                     str->u.chars = NULL;
 686                 } else {
 687                     key = js_NewStringCopyN(cx, JSFLATSTR_CHARS(str),
 688                                             JSFLATSTR_LENGTH(str));
 689                     if (!key)
 690                         return NULL;
 691                 }
 692            } else {
 693                 JS_ASSERT(JSSTRING_IS_DEPENDENT(str));
 694                 if (!js_UndependString(cx, str))
 695                     return NULL;
 696                 key = str;
 697             }
 698
 699             JS_LOCK(cx, &state->lock);
 700             if (table->generation == gen) {
 701                 JS_ASSERT(entry->keyAndFlags == 0);
 702             } else {
 703                 entry = TO_ATOM_ENTRY(JS_DHashTableOperate(table, key,
 704                                                            JS_DHASH_ADD));
 705                 if (!entry)
 706                     goto failed_hash_add;
 707                 if (entry->keyAndFlags != 0) {
 708                     key = (JSString *)ATOM_ENTRY_KEY(entry);
 709                     goto finish;
 710                 }
 711                 ++table->generation;
 712             }
 713         }
 714         INIT_ATOM_ENTRY(entry, key);
 715         JSFLATSTR_SET_ATOMIZED(key);
 716     }
 717
 718   finish:
 719     ADD_ATOM_ENTRY_FLAGS(entry, flags & (ATOM_PINNED | ATOM_INTERNED));
 720     JS_ASSERT(JSSTRING_IS_ATOMIZED(key));
 721     v = STRING_TO_JSVAL(key);
 722     cx->weakRoots.lastAtom = v;
 723     JS_UNLOCK(cx, &state->lock);
 724     return (JSAtom *)v;
 725
 726   failed_hash_add:
 727     JS_UNLOCK(cx, &state->lock);
 728     JS_ReportOutOfMemory(cx);
 729     return NULL;
 730 }
 731
 732 JSAtom *
 733 js_Atomize(JSContext *cx, const char *bytes, size_t length, uintN flags)
 734 {
 735     jschar *chars;
 736     JSString str;
 737     JSAtom *atom;
 738
 739     /*
 740      * Avoiding the malloc in js_InflateString on shorter strings saves us
 741      * over 20,000 malloc calls on mozilla browser startup. This compares to
 742      * only 131 calls where the string is longer than a 31 char (net) buffer.
 743      * The vast majority of atomized strings are already in the hashtable. So
 744      * js_AtomizeString rarely has to copy the temp string we make.
 745      */
 746 #define ATOMIZE_BUF_MAX 32
 747     jschar inflated[ATOMIZE_BUF_MAX];
 748     size_t inflatedLength = ATOMIZE_BUF_MAX - 1;
 749
 750     if (length < ATOMIZE_BUF_MAX) {
 751         js_InflateStringToBuffer(cx, bytes, length, inflated, &inflatedLength);
 752         inflated[inflatedLength] = 0;
 753         chars = inflated;
 754     } else {
 755         inflatedLength = length;
 756         chars = js_InflateString(cx, bytes, &inflatedLength);
 757         if (!chars)
 758             return NULL;
 759         flags |= ATOM_NOCOPY;
 760     }
 761
 762     JSFLATSTR_INIT(&str, (jschar *)chars, inflatedLength);
 763     atom = js_AtomizeString(cx, &str, ATOM_TMPSTR | flags);
 764     if (chars != inflated && str.u.chars)
 765         JS_free(cx, chars);
 766     return atom;
 767 }
 768
 769 JSAtom *
 770 js_AtomizeChars(JSContext *cx, const jschar *chars, size_t length, uintN flags)
 771 {
 772     JSString str;
 773
 774     JSFLATSTR_INIT(&str, (jschar *)chars, length);
 775     return js_AtomizeString(cx, &str, ATOM_TMPSTR | flags);
 776 }
 777
 778 JSAtom *
 779 js_GetExistingStringAtom(JSContext *cx, const jschar *chars, size_t length)
 780 {
 781     JSString str, *str2;
 782     JSAtomState *state;
 783     JSDHashEntryHdr *hdr;
 784
 785     JSFLATSTR_INIT(&str, (jschar *)chars, length);
 786     state = &cx->runtime->atomState;
 787
 788     JS_LOCK(cx, &state->lock);
 789     hdr = JS_DHashTableOperate(&state->stringAtoms, &str, JS_DHASH_LOOKUP);
 790     str2 = JS_DHASH_ENTRY_IS_BUSY(hdr)
 791            ? (JSString *)ATOM_ENTRY_KEY(TO_ATOM_ENTRY(hdr))
 792            : NULL;
 793     JS_UNLOCK(cx, &state->lock);
 794
 795     return str2 ? (JSAtom *)STRING_TO_JSVAL(str2) : NULL;
 796 }
 797
 798 JSBool
 799 js_AtomizePrimitiveValue(JSContext *cx, jsval v, JSAtom **atomp)
 800 {
 801     JSAtom *atom;
 802
 803     if (JSVAL_IS_STRING(v)) {
 804         atom = js_AtomizeString(cx, JSVAL_TO_STRING(v), 0);
 805         if (!atom)
 806             return JS_FALSE;
 807     } else if (JSVAL_IS_DOUBLE(v)) {
 808         atom = js_AtomizeDouble(cx, *JSVAL_TO_DOUBLE(v));
 809         if (!atom)
 810             return JS_FALSE;
 811     } else {
 812         JS_ASSERT(JSVAL_IS_INT(v) || JSVAL_IS_BOOLEAN(v) ||
 813                   JSVAL_IS_NULL(v) || JSVAL_IS_VOID(v));
 814         atom = (JSAtom *)v;
 815     }
 816     *atomp = atom;
 817     return JS_TRUE;
 818 }
 819
 820 JSBool
 821 js_ValueToStringId(JSContext *cx, jsval v, jsid *idp)
 822 {
 823     JSString *str;
 824     JSAtom *atom;
 825
 826     /*
 827      * Optimize for the common case where v is an already-atomized string. The
 828      * comment in jsstr.h before the JSSTRING_SET_ATOMIZED macro's definition
 829      * explains why this is thread-safe. The extra rooting via lastAtom (which
 830      * would otherwise be done in js_js_AtomizeString) ensures the caller that
 831      * the resulting id at is least weakly rooted.
 832      */
 833     if (JSVAL_IS_STRING(v)) {
 834         str = JSVAL_TO_STRING(v);
 835         if (JSSTRING_IS_ATOMIZED(str)) {
 836             cx->weakRoots.lastAtom = v;
 837             *idp = ATOM_TO_JSID((JSAtom *) v);
 838             return JS_TRUE;
 839         }
 840     } else {
 841         str = js_ValueToString(cx, v);
 842         if (!str)
 843             return JS_FALSE;
 844     }
 845     atom = js_AtomizeString(cx, str, 0);
 846     if (!atom)
 847         return JS_FALSE;
 848     *idp = ATOM_TO_JSID(atom);
 849     return JS_TRUE;
 850 }
 851
 852 #ifdef DEBUG
 853
 854 static JSDHashOperator
 855 atom_dumper(JSDHashTable *table, JSDHashEntryHdr *hdr,
 856             uint32 number, void *arg)
 857 {
 858     JSAtomHashEntry *entry = TO_ATOM_ENTRY(hdr);
 859     FILE *fp = (FILE *)arg;
 860     void *key;
 861     uintN flags;
 862
 863     fprintf(fp, "%3u %08x ", number, (uintN)entry->hdr.keyHash);
 864     if (entry->keyAndFlags == 0) {
 865         fputs("<uninitialized>", fp);
 866     } else {
 867         key = ATOM_ENTRY_KEY(entry);
 868         if (IS_DOUBLE_TABLE(table)) {
 869             fprintf(fp, "%.16g", *(jsdouble *)key);
 870         } else {
 871             JS_ASSERT(IS_STRING_TABLE(table));
 872             js_FileEscapedString(fp, (JSString *)key, '"');
 873         }
 874         flags = ATOM_ENTRY_FLAGS(entry);
 875         if (flags != 0) {
 876             fputs((flags & (ATOM_PINNED | ATOM_INTERNED))
 877                   ? " pinned | interned"
 878                   : (flags & ATOM_PINNED) ? " pinned" : " interned",
 879                   fp);
 880         }
 881     }
 882     putc('\n', fp);
 883     return JS_DHASH_NEXT;
 884 }
 885
 886 JS_FRIEND_API(void)
 887 js_DumpAtoms(JSContext *cx, FILE *fp)
 888 {
 889     JSAtomState *state = &cx->runtime->atomState;
 890
 891     fprintf(fp, "stringAtoms table contents:\n");
 892     JS_DHashTableEnumerate(&state->stringAtoms, atom_dumper, fp);
 893 #ifdef JS_DHASHMETER
 894     JS_DHashTableDumpMeter(&state->stringAtoms, atom_dumper, fp);
 895 #endif
 896     putc('\n', fp);
 897
 898     fprintf(fp, "doubleAtoms table contents:\n");
 899     JS_DHashTableEnumerate(&state->doubleAtoms, atom_dumper, fp);
 900 #ifdef JS_DHASHMETER
 901     JS_DHashTableDumpMeter(&state->doubleAtoms, atom_dumper, fp);
 902 #endif
 903     putc('\n', fp);
 904 }
 905
 906 #endif
 907
 908 static JSHashNumber
 909 js_hash_atom_ptr(const void *key)
 910 {
 911     const JSAtom *atom = (const JSAtom *) key;
 912     return ATOM_HASH(atom);
 913 }
 914
 915 static void *
 916 js_alloc_temp_space(void *priv, size_t size)
 917 {
 918     JSContext *cx = (JSContext *) priv;
 919     void *space;
 920
 921     JS_ARENA_ALLOCATE(space, &cx->tempPool, size);
 922     if (!space)
 923         js_ReportOutOfScriptQuota(cx);
 924     return space;
 925 }
 926
 927 static void
 928 js_free_temp_space(void *priv, void *item)
 929 {
 930 }
 931
 932 static JSHashEntry *
 933 js_alloc_temp_entry(void *priv, const void *key)
 934 {
 935     JSContext *cx = (JSContext *) priv;
 936     JSAtomListElement *ale;
 937
 938     JS_ARENA_ALLOCATE_TYPE(ale, JSAtomListElement, &cx->tempPool);
 939     if (!ale) {
 940         js_ReportOutOfScriptQuota(cx);
 941         return NULL;
 942     }
 943     return &ale->entry;
 944 }
 945
 946 static void
 947 js_free_temp_entry(void *priv, JSHashEntry *he, uintN flag)
 948 {
 949 }
 950
 951 static JSHashAllocOps temp_alloc_ops = {
 952     js_alloc_temp_space,    js_free_temp_space,
 953     js_alloc_temp_entry,    js_free_temp_entry
 954 };
 955
 956 JSAtomListElement *
 957 js_IndexAtom(JSContext *cx, JSAtom *atom, JSAtomList *al)
 958 {
 959     JSAtomListElement *ale, *ale2, *next;
 960     JSHashEntry **hep;
 961
 962     ATOM_LIST_LOOKUP(ale, hep, al, atom);
 963     if (!ale) {
 964         if (al->count < 10) {
 965             /* Few enough for linear search, no hash table needed. */
 966             JS_ASSERT(!al->table);
 967             ale = (JSAtomListElement *)js_alloc_temp_entry(cx, atom);
 968             if (!ale)
 969                 return NULL;
 970             ALE_SET_ATOM(ale, atom);
 971             ale->entry.next = al->list;
 972             al->list = &ale->entry;
 973         } else {
 974             /* We want to hash.  Have we already made a hash table? */
 975             if (!al->table) {
 976                 /* No hash table yet, so hep had better be null! */
 977                 JS_ASSERT(!hep);
 978                 al->table = JS_NewHashTable(al->count + 1, js_hash_atom_ptr,
 979                                             JS_CompareValues, JS_CompareValues,
 980                                             &temp_alloc_ops, cx);
 981                 if (!al->table)
 982                     return NULL;
 983
 984                 /*
 985                  * Set ht->nentries explicitly, because we are moving entries
 986                  * from al to ht, not calling JS_HashTable(Raw|)Add.
 987                  */
 988                 al->table->nentries = al->count;
 989
 990                 /* Insert each ale on al->list into the new hash table. */
 991                 for (ale2 = (JSAtomListElement *)al->list; ale2; ale2 = next) {
 992                     next = ALE_NEXT(ale2);
 993                     ale2->entry.keyHash = ATOM_HASH(ALE_ATOM(ale2));
 994                     hep = JS_HashTableRawLookup(al->table, ale2->entry.keyHash,
 995                                                 ale2->entry.key);
 996                     ale2->entry.next = *hep;
 997                     *hep = &ale2->entry;
 998                 }
 999                 al->list = NULL;
1000
1001                 /* Set hep for insertion of atom's ale, immediately below. */
1002                 hep = JS_HashTableRawLookup(al->table, ATOM_HASH(atom), atom);
1003             }
1004
1005             /* Finally, add an entry for atom into the hash bucket at hep. */
1006             ale = (JSAtomListElement *)
1007                   JS_HashTableRawAdd(al->table, hep, ATOM_HASH(atom), atom,
1008                                      NULL);
1009             if (!ale)
1010                 return NULL;
1011         }
1012
1013         ALE_SET_INDEX(ale, al->count++);
1014     }
1015     return ale;
1016 }
1017
1018 static intN
1019 js_map_atom(JSHashEntry *he, intN i, void *arg)
1020 {
1021     JSAtomListElement *ale = (JSAtomListElement *)he;
1022     JSAtom **vector = (JSAtom **) arg;
1023
1024     vector[ALE_INDEX(ale)] = ALE_ATOM(ale);
1025     return HT_ENUMERATE_NEXT;
1026 }
1027
1028 #ifdef DEBUG
1029 static jsrefcount js_atom_map_count;
1030 static jsrefcount js_atom_map_hash_table_count;
1031 #endif
1032
1033 void
1034 js_InitAtomMap(JSContext *cx, JSAtomMap *map, JSAtomList *al)
1035 {
1036     JSAtom **vector;
1037     JSAtomListElement *ale;
1038     uint32 count;
1039
1040     /* Map length must already be initialized. */
1041     JS_ASSERT(al->count == map->length);
1042 #ifdef DEBUG
1043     JS_ATOMIC_INCREMENT(&js_atom_map_count);
1044 #endif
1045     ale = (JSAtomListElement *)al->list;
1046     if (!ale && !al->table) {
1047         JS_ASSERT(!map->vector);
1048         return;
1049     }
1050
1051     count = al->count;
1052     vector = map->vector;
1053     if (al->table) {
1054 #ifdef DEBUG
1055         JS_ATOMIC_INCREMENT(&js_atom_map_hash_table_count);
1056 #endif
1057         JS_HashTableEnumerateEntries(al->table, js_map_atom, vector);
1058     } else {
1059         do {
1060             vector[ALE_INDEX(ale)] = ALE_ATOM(ale);
1061         } while ((ale = ALE_NEXT(ale)) != NULL);
1062     }
1063     ATOM_LIST_INIT(al);
1064 }